Articulated hand

• US 5,062,673 A
• Filed: 12/28/1989
• Issued: 11/05/1991
• Est. Priority Date: 12/28/1988
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho (Toyota Motor Corporation)
• Original Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho (Toyota Motor Corporation)
• Inventors: Mimura, Nobuharu
• Primary Examiner(s): Focarino, Margaret A.
• Assistant Examiner(s): Kramer, Dean J.
• Application Number:
  US07/458,346
• Time in Patent Office: 677 Days
• Field of Search: 294/111, 294/106, 294/907, 901/30-34, 901/36-39, 901/46, 901/21, 623/57, 623/63, 623/64, 414/5, 414/6, 414/7
• US Class Current: 294/111
• CPC Class Codes: B25J 15/0009 comprising multi-articulated fingers, e.g. resembling a human hand
• CPC Class Codes: Y10S 294/907 Sensor controlled device

Abstract

An articulated hand comprising a plurality of finger module structures each of which has one top end provided with an abutting member for contacting an object and the other end connected to a finger connecting member and has a plurality of articulates formed between the one and the other ends by combination of a plurality of link members and articulate turn-shafts; a plurality of motors provided at the other ends of the respective finger module structures integrally therewith; a power transmitting device for transmitting motor powers to the articulate turn-shaft and a hand structure connected to a manipulator. The finger modules are arranged in a manner so that the articulate shafts are driven independently of each other, and each of the link members is provided with sensors respectively for directly detecting a relative angle and relative torque between adjacent link members. Each of the articulate turn-shafts is provided with an angel-torque servo system, wherein deviation signals based on the relative angle and torque are processed. In the articulated hand, each of the motors is connected to a variable constant-current source to change its power through changing an instruction current value and values of motor revolution speed obtained from driving voltages of the motors are respectively fed back to the servo systems to thereby correct the instruction current values.

Claims

1. An articulated hand comprising:

a plurality of finger module structures each of which has a top end provided with an abutting member for contacting an object and an other end connected to a finger connecting member and has a plurality of articulates formed between said top end and said other end by a plurality of link members rotatably mounted on articulate turn-shafts so that said articulates are capable of being bent and stretched both in a first direction vertical to the longitudinal direction of said finger module structure and in a second direction perpendicular to said first direction;

a plurality of motors provided at said other end of each of said finger module structures integrally therewith in a manner so as to give torque to said link members through power transmitting means to thereby freely bend and stretch said link members independently of each other; and

a hand structure connected to a manipulator so as to arrange at least one of said finger module structures in opposition to at least one other of said finger module structures and so as to change a distance between said finger module structures in opposition to each other through the operation of said motors to bring said finger structures into contact with said object;

wherein

said finger module structures are arranged in a manner so that said articulate turn-shafts are driven independently of each other,

each of said link members is provided with sensors respectively for directly detecting a relative angle and a relative torque between adjacent link members, and

independent angle-torque servo systems are provided for each of said articulate turn-shafts for comparing said relative angle and torque directly detected by said angle and torque sensors with a desired value thereof and processing resultant deviation signals therebetween; and

wherein each of said motors is connected to a variable constant-current source to change its power through changing an instruction current value and wherein values of motor revolution speed obtained from driving voltages of said motors are respectively fed back to servo systems to thereby correct said instruction current values so that damping may be applied to said angle-torque servo systems.

3. An apparatus according to claim 1, wherein said at least one of said finger module structures has three of said articulate turn-shafts such that the position of the finger top and a force produced in the finger top can be designed freely in three dimensions.

2. An articulated hand comprising:

a plurality of finger module structures each of which has a top end provided with an abutting member for contacting an object and an other end connected to a finger connecting member and has a plurality of articulates formed between said top end and said other end by a plurality of link members rotatably mounted on articulate turn-shafts so that said articulates are capable of being bent and stretched both in a first direction vertical to the longitudinal direction of said finger module structure and in a second direction perpendicular to said first direction;

a plurality of motors provided at said other end of each of said finger module structures integrally therewith in a manner so as to give torque to said link members through power transmitting means to thereby freely bend and stretch said link members independently of each other; and

a hand structure connected to a manipulator so as to arrange at least one of said finger module structures in opposition to at least one other of said finger module structures and so as to change a distance between said finger module structures in opposition to each other through the operation of said motors to bring said finger structures into contact with said object;

wherein

said finger module structures are arranged in a manner so that said articulate turn-shafts are driven independently of each other,

each of said link members is provided with sensors respectively for directly detecting a relative angle and a relative torque between adjacent link members, and

independent angle-torque servo systems are provided for each of said articulate turn-shafts for comparing said relative angle and torque directly detected by said angle and torque sensors with a desired value thereof and processing resultant deviation signals therebetween; and

wherein each of said angle-torque servo systems comprises means for calculating motor revolution speed (Nm) on the basis of a difference between motor voltage (Vg) and a product of rotor resistance (Rm) of the motor output current (Im) of the variable constant-current source.

4. An articulated hand comprising:

a plurality of finger module structures each of which has a top end provided with an abutting member for contacting an object and an other end connected to a finger connecting member and has a plurality of articulates formed between said top end and said other end by a plurality of link members rotatably mounted on articulate turn-shafts so that said articulates are capable of being bent and stretched both in a first direction vertical to the longitudinal direction of said finger module structure and in a second direction perpendicular to said first direction;

a plurality of motors provided at said other end of each of said finger module structures integrally therewith in a manner so as to give torque to said link members through power transmitting means to thereby freely bend and stretch said link members independently of each other; and

a hand structure connected to a manipulator so as to arrange at least one of said finger module structures in opposition to at least one other of said finger module structures and so as to change a distance between said finger module structures in opposition to each other through the operation of said motors to bring said finger structures into contact with said object;

wherein

said finger module structures are arranged in a manner so that said articulate turn-shafts are driven independently of each other,

each of said link members is provided with sensors respectively for directly detecting a relative angle and a relative torque between adjacent link members, and

independent angle-torque servo systems are provided for each of said articulate turn-shafts for comparing said relative angle and torque directly detected by said angle and torque sensors with a desired value thereof and processing resultant deviation signals therebetween; and

wherein said abutting member is provided at said top end of said finger structure and is composed of a rod-like core member having a screw portion at one end, a base member substantially conically shaped in its external appearance and formed of softer material than that of the rod-like core member, an other base member shaped like a human finger top in its external appearance and formed of softer material than that of said base member, and an elastic skin member shaped like a human finger top in its external appearance and subjected to a surface treatment for patterning its outer surface with fine bosses or wrinkles to increase the coefficient of friction of said skin member, said rod-like core member being inserted in a center of said conically shaped base member, said skin member being fixed to an exterior surface of said other base member so as not to be peeled off.

5. An articulated hand comprising at least one finger module structure and a finger connecting member in which said one finger module structure comprises:

a plurality of articulate portions having link members for forming the finger structure and articulate turn-shafts for rotatably connecting said link members;

power transmitting means for freely bending and stretching said link members independently; and

drive means connected to a variable constant-current source so as to change power to said drive means by changing an instruction current value;

sensor means for directly detecting an interlink angle between adjacent link members and for directly detecting relative torque between adjacent link members; and

an independent angle-torque servo system provided for each of said articulate turn-shafts in order to move said articulate turn-shafts independently of one another based on the interlink angle and torque detected by said sensor means;

and wherein values of driving revolution speed obtained from driving voltages of said drive means are respectively fed back to said servo systems to thereby correct said instruction current values so that damping may be applied to said angle-torque servo systems.

6. An articulated hand according to claim 5, in which said finger module structure has one top end provided with an abutting member for contacting a subject and an other end connected to said finger connecting member wherein said articulate portions are formed between said one and said other ends by said link member and said articulate turn-shafts so that said articulates are capable of being bent and stretched both in a first direction vertical to the longitudinal direction of said finger structure and in a second direction perpendicular to said first direction.

7. An articulated hand according to claim 6, wherein said drive means is provided at said other end of each of said finger module structures in a manner so as to provide torque to said link members through said power transmitting means to thereby freely bend and stretch said link members independently of each other.

8. An articulated hand according to claim 7, wherein said abutting member is composed of a rod-like core member having a screw portion at its one end, a base member substantially conically shaped in its external appearance and formed of softer material than that of the rod-like core member, another base member shaped like a human finger top in its external appearance and formed of softer material than that of said base member, and an elastic skin member shaped like a human finger top in its external appearance and subjected to a surface treatment for patterning its outer surface with fine bosses or wrinkles to increase the coefficient of friction of said skin member, said rod-like core member being inserted in a center of said conically shaped base member, said skin member being fixed to an exterior surface of said base member so as not to be peeled off, wherein said articulated hand is connected to a manipulator.

9. An articulated hand having a plurality of individually actuatable finger modules for grasping an object, wherein:

each of said finger modules is interchangeable with every other finger module of said articulated hand;

each of said finger modules includes a plurality of link members pivoted to one another;

each link member of a given finger module is operated by a separate electric motor provided on said given finger module;

each link member of said given finger module includes sensor means for directly detecting a relative angle between adjacent link members and for directly detecting a relative torque between adjacent link members;

each link member of said given finger module is independently controlled by a control means located on said given finger module, said control means controlling a voltage to said electric motor;

said control means includes a means for processing said relative angle and said relative torque; and

wherein

said independent control means further includes a compensator responsive to said means for processing, said compensator producing a signal which effects the control of said voltage.